Process of producing sponge iron



May 6 1924. 1,492,818

E. B. THORNHILL PROCESS OF PRODUCING SPONGE IRON Filed Jan. 8, 1920 2 Sheets-Sheet l IN VEN TOR.

A T TORNEYS.

May G, 1924. A l 1,492,818

E. B. THORNHILL PROCESS OF PRODUCING SPONGE IRON Filed dan. 8, 1920 t 2 Sheets-Sheet 2 Iliff/1111111111111 Ill/111111111111111 V f/ if INVENTOR.

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Patented May 6, 1924.

'PATENT oFFlZcE..

EDWIN B. THORNHILL, F HURLEY, MEXICO.

PROCESS OF PRODUCING SPONGE 113.0151'.

Application led January To all whom t mag/ ooncem:

Be it known that I, EDWIN B. THORNHILL, a citizen of the United States, residing at Hurley, in the county of Grant and State of New Mexico, have invented certain new and useful Improvements in Processes of Producing Sponge Iron, of which the following is a specification.

This invention relates to improvements in l0 process for producing sponge iron.

In the concentration of copper, forlexample, where leaching operations are'conducted, it has been found that sponge iron,

- preferably in comminuted form, is highly advantageous in producing `what I term amorphous copper in the shape of a occu,

lent precipitate.

My present invention relates to the process ,but also the semi-coke or coke for re-use asa of lobtaining this sponge iron from the ore in which it naturallyoccurs or from artificial iron compounds, such as Fe2O3, simlar to hematite and obtained by calcinin or pre-roasting of iron ores in which the iron occurs in various compounds, such as siderite, limonite, etc. I also. contemplate the use of calcined iron pyrite and magnetite and hematite in its natural condition.

In some instances I find it desirable to preheat the natural substances, as well as those the carrying out ofmy process and reduce the expense thereof.

My process consists briefiy in the heating to the desired temperature in retorts of the iron bearing constituent mixed with the necessary proportion of a reducing agent, such as coal, hydrocarbon oils, or the like, together with an excess of carbonaceous material, such as coke, semicoke, as I termit, which will be defined hereinbelow, or other materials, which is not utilized to reduce the iron bearing constituent, but is utilized to.

prevent cohesion of the sponge iron particles resulting from the reduction. The iron at the time of its conversion from the compound, in which it occurs, to the pure sponge state will not combine with the excess of.

an agglomerated product, even thou h -the j latter may be of pure iron, since vhave which I may calcine, in order to expedite 8, 1920. Serial No. 350,171.

i stituent in my process, the same is allowed to cool in a neutral orreducing atmosphere to a. polnt below that at which oxidation readily occurs and the diluent material and sponge iron is thereafter removed from the v cooling receptacle and the iron particles sep.- arated from the remainder of the discharged product by means of a magnetic separator, or the like, which separates the diluent and other non-iron material from the sponge iron so that I may not only retain the iron,

Fig.f 1 is a vertical section through the' furnace of my apparatus, portions of the retorts therein being shown as broken away .and other portions ofthe apparatus being shown in elevation.

.`F1g. '2 is a transverse horizontal section along the line 2--2 of Fig. 1.

Fig. 3 is a similar section along the line v Aafa of Fig. 1.

In the drawings 10 designates generally the casing forming a part of the furnace generally and having a. chimney 10 extending upwardly therefrom. Located at the bottom of the furnace 10 is the grate 10b' of conventional construction, the fire box formed by such grate being`in communication with the casing' 10 by means of a passage 10, see Fig. 1. Locatedwithin'the casing 10 4and spaced therefrom-'and fromv each other are the vertical retorts 11, these retorts being for convenience composed of the sections 11a,.each section being provided vwith a seat or socket for the interitting end of the'next section above. AI have shown these retort sections as constructed' of refractory material, .preferably carbonaceous refractory material, as carborundum, or the like, and having a carbon linin such as raphite, indicated by numera 11", see ig. 2.

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One purpose of this retort construction is to prevent the adherence of the sponge 1ron to the sides of the retort. Horizontal bafiies 12 are located at suitable points within the casing 10, these battles being supported upon the ledges 10 of the furnace 1f) and extending partially across the interior thereof in such wise as to form staggered circulation openings 10d. 'A bottom plate 13 extends across the entire area of the furnace thereby' sealing the chamber 1,()e of the furnace from passa-ge of the heating gases therethrough, this chamber being open at 10t to the outside atmosphere and constitutin a cooling chamber, it being maintaine at a temperature greatly below that of the heating portion of the furnace. The heating gases flow from the lire box through the opening 10 and thereafter circulate around the retorts 11 until they finally How out through the chimney 10a, such ow being caused also by the closing of the top of the furnace 10 by a cover plate 14. A

' rotatable damper 15 is provided in the chimney 10% to control the ow of gas therethrough',

Located in the cooling chamber 10e are the cooling receptacles 16 preferably constructed of cast iron, or the like, to insure rapid radiation and conduction of the heat from the reduced material. These receptacles are in communication with the interior of the retorts, as shown in the drawings, and are located above the collection hopper 17 into which their contents may be discharged by proper actuation of the slides or gates 17a having engageable handles or portions 17. The hopper 17 has the outwardly engaging discharge duct 18 and a screw conveyor 19 is rotatably mounted in the hopper 17 and duct 18, being provided with a central shaft 19a hollow to permit circulation of cooling uid, such vas water, therethrough, the same being supplied to one end by the tube 2O and discharged at -the other end through the tube 21. A suitable gear 22 is mounted on theshaft 19a and is rotated by the pinion 23 carried on the shaft 24 and rotated by a suitable motor 25, or the like. The discharge pipe is provided with the outlet 18a. Located beneath the discharge 18a is the belt 26 and the magnetic separating unit comprising the drive pulley 27 and drum or cobber 28 provided with suitable magnets 29 excited by means of current from a source 30 from which lead the feed wires 31, for example. In the operation of this separator, as is well known, the iron particles will be retained on the surface of the drum 28 a suiicient period of travel to insure their deposit in the collection space 45; while the non-iron particles will be projected a suicient distance to be deposited in the collection space 50.

In the carrying out of my process, as described above, in actual practice I have mixed three parts of ma-gnetite with one part cf Gallup coal, the latter being a coal obtained from the vicinity of Gallup, New

Mexico, being technicallylmown as non-cok- Gallup coal mentioned above, although thev coal at the conclusion of theV treatment, during which the volatile constituents have been driven 0E, does not resemble coke in appearance, texture, or the like. These ingredients are fed into the hop pers 40, assuming the furnace to have been in operation, and are fed vertically downwardly through the retorts 'during which passage the heat,

being'maintained at the proper degree, will reduce the iron bea-ring constituent, i. e.,

Gallup coal compounds with the oxygen of.

the iron compound leaving the iron in the form of sponge iron, as I term it, which settling'into the receptacles 16 will be rapidly cooled therein and since the latter are solocated and constructed that substantially no oxygen will reach the interior thereof from the outside atmosphere, a neutral or reducing'atmosphere is maintained in such receptacles. In 'the latter, the iron is cooled to a point below that at which oxidation will readily take place and at proper intervals of time the gates 17a may be actuated to deposit charges of the material into the hopper 17 from which the same is fed by the screw conveyor 19 to the separator belt 26. additional cooling being obtained in the hopper during the discharge of the product by means of rotation and the cooling eli'ect of the water cooled conveyor. As will be obvious, the magnetic separator in a well known manuel will separat-e the principal sponge iron from the other material, which latter will, for the most part, be the socalled semi-coke or actual coke, which I am able to re-use as a diluent in the carrying out of this process. i l

It is to be noted that I do not wish to restrict myself to these specific ingredients, but contemplate the use of any suitable reducing medium and any suitable carbonaccous diluent, such as coke, or the like.

As explained above, the dilueut. is inert in so far as the carrying out of the process is concerned and serves to prevent agglomeration of the iron particles when they7 are at the heat of reduction, at which time a less suflicient quantity of carbonacecns material is present, such agglomeration will take place.

It will be obvious that by proper regi-.la-

tion and operation of the apparatus described my process may be carried on continuously in contrast to the use of retorts which must be charged, cooled and discharged intermittently.

It will also be obvious that my process is susceptible to numerous modifications and improvements and I do not Wish to be restricted to the same asdescribed and shown herewith except as defined in the appended claim, nor do I Wish to be restricted to the specic form of apparatus described and shown for the carrying out of myl process.

What I claim is r A process of the class described consisting in mixing iron ore with a reducing agent, thereafter passingthe same through a carbon lined retort externally heated to maintain a reducing atmosphere in said retort, then cooling the reduced iron in a non-oxidizing atmosphere, and separa-ting the iron from the non-iron materiaL n testimony whereof, l have subscribed my name..

EDWIN B. THORNHILL. 

